Windows/Mac and iOS: Need a bit of extra screen real estate? iDisplay can turn your iPad into a second monitor for your Mac or Windows PC, and it's on sale for $1.99 right now.

iDisplay, usually $5, is a cheap, easy way to extend your desktop onto your tablet. $5 can sometimes seem like a hefty price, especially when you can't test an app out first, so it's great that iDisplay is on sale for $1.99 in the App Store. Unfortunately, the Android version is still full price, but if you're armed with an iPad, head over to the App Store and grab your discounted copy while you can.